1. Field of the Invention
The present invention relates to an apparatus for controlling fuel injection and to a method for controlling fuel injection in an internal combustion engine which includes a first intake passage provided with a first fuel injection valve, and a second intake passage provided with a second fuel injection valve, for each cylinder.
2. Description of Related Art
Japanese Laid-open Patent Publication No. 2010-038102 discloses an internal combustion engine including a first fuel injection valve disposed in a first intake passage and a second fuel injection valve disposed in a second intake passage, and furthermore, discloses a fuel injection control apparatus for an internal combustion engine to inject fuel to the internal combustion engine by using both the first fuel injection valve and the second fuel injection valve.
However, as the fuel injection control apparatus disclosed in the above, in a case in which fuel is injected into the internal combustion engine by using both the first fuel injection valve and the second fuel injection valve, which are disposed in the vicinity of a cylinder, the fuel amount from the fuel injected from each fuel injection valve adhering to an inner wall of an intake passage increases. Furthermore, since more fuel adheres to the inner wall of the intake passage in each cycle, an equilibrium amount of adhering fuel to the inner wall of the intake passage increases.
When the equilibrium amount of adhering fuel to the inner wall of the intake passage is large, fluctuation of an air fuel ratio during transient operation becomes large. Accordingly, there has been a problem of worsening of exhaust emission and fuel consumption performance.